Grinding machine



Oct. 9, 1945. B, MacNElLL 2,386,742

GRINDING MACHINE Filed Dec. 30, 1944' 5 Sheets-Sheet i Iawenor Oct. 9,1945. MaCNEILL GRINDING MACHINE Fi led Dec. so, 1944 5 Sheets-Sheet sflii'owneya Patented Oct. 9, 1945 UNITED STATES PATENT OFFICE GRINDINGMACHINE Arden B. MacNeill, Waltham, Mass.

Application December 30, 1944, Serial No. 570,710

2 Claims.

This invention relates to grinders for accurately grinding to extremelyclose tolerances the exposed ends of tubular blanks or other workpieces. These work pieces are usually of small size and have to befinished in large quantities and at low cost, and accordingly the mainobject of my invention is to provide an efiicient and reliable machineof compact size and simple design for performing this work. Otherobjects and advantages will appear as this description proceeds.

In a preferred embodiment of my invention, my machine comprises ahorizontally disposed rotatable feed wheel having about its periphery aplurality of spaced vertically disposed notches constitutingwork-holding pockets. Each pocket is preferably of a size to snuglyreceive a single work piece placed endwise therein and of a depthslightly less than the length of the work piece so that the upper endsofthe work pieces project slightly beyond the upper face of the feedwheel.

The feed wheel is constantly rotated in the same direction about avertical axis to successively present the exposed ends of the workpieces held within said pockets to a pair of spaced overhead grindingwheels which are constantly rotated about axes at right angles to theaxis of rotation of the feed wheel.

Preferably the grinding wheels are disposedopposite to each other ateither side of the feed wheel shaft so as successively to act upon theexposed ends of the work pieces as the rotation of the feed wheelcarries them beneath each grinding wheel.

Preferably also, the first grinding wheel to contact the work pieces isset to rough grind from the work pieces substantially all of thematerial thereof projecting beyond the upper face of the work wheel. Thesecond grinding wheel finishes the work pieces totheir final dimensionswhen said pieces in the continued rotation of the feed wheel are carriedfrom beneath the first grinding wheel to beneath said second grindingwheel.

The work pieces are ready to be ejected from the pockets of the feedwheel one at a time and discharged from the machine, such dischargeoccurring at a later point in the cycle of the feed wheel.

Suitable mechanism is provided for positively confining the work piecesin the holding pockets of the feed wheel while in orbit and until readyto be discharged, and also for exerting additional confining pressureupon the work pieces when they reach the points in their orbit at whichtheir projecting upper ends are contacted by the respective grindingwheels.

The operation of my machine is practically automatic. The workman needsonly to keep the pockets of the feed wheel filled with work pieces,since the continuous rotation of the feed wheel successively carries thework pieces from one grinding wheel to the other and finally to theirdischarge point.

An illustrative embodiment of my machine is shown in the accompanyingdrawings, wherein:

Fig. l is a horizontal plan section of my machine.

Fig. 2 is a front elevation, partly broken away.

Fig. 3 is an enlarged top plan view of the feed wheel and associatedparts, and

Fig. 4 is a section on the line !I4, of Fig. 3.

My machine comprises a frame I0 on which is horizontally supported acentral base II and a trough I2. The base I I supports my novel feedwheel. .The trough I2 establishes a reservoir for the coolant for thegrinding wheels.

My feed wheel includes a stationary lower member I3 resting on base IIand a superposed revolving upper member I4. Surrounding said members isa segmental ring I5 which is fixed to the frame and is of a heightsubstantially equal to the combined thickness of said members. Ring I5is peripherally cut away as at A, B and C (see Fig. 3) for a purpose .tobe later explained.

Revolving member I4 is provided at its periphery with a plurality ofspaced notches I'I constituting vertically disposed work-holding pocketsfor the work pieces W, the bottoms of said pockets being furnished bythe underlying stationary member I3. The notches I! are preferably ofV-shape with their wide ends opening out to the perimeter of member I4.

The work pieces or blanks may be tubular, as shown, and are insertedendwise one in each pocket H. In length, they slightly exceed the depthof the pockets, so that their upper ends project slightly above theupper face of member I4, as indicated in dotted lines at the right inFig. 4. The distance that. the upper ends of the work pieces projectbeyond the upper face of member I4 may correspond approximately to theamount of material to be removed therefrom by the grinding wheels.

The work pieces are held within the pockets, until ready to bedischarged, by means of a band spring I8 extending around the perimeterof the revolving member I4 from anchor point I9 to anchor point 20 onmember I5 (see Fig. 3).

Member I4 is driven as follows. Both it, member I3, and base I! aredrilled to receive a stud shaft 2| which is flanged as at 22 andfastened as at 23 to member I4 (see Fig. 4). The-fit of stud shaft 2I inparts I3 and II is tight enough to overcome any tendency towardswobbling but not tight enough to impart rotation to said parts. Theupper end of stud shaft 2| is bored as at 24 and cross-slotted as at 25to receive. respectively, the lower end of drive shaft 26 and fasteningpin 21. This form of driving connection permits wheels of differentthickness to be interchangeably used in the machine.

Drive shaft 26 is journaled at its upper end in any suitable bearing 28(see Fig. 2) and is constantly driven from any suitable power source, asthe shaft 42 through gears 29 and 29 on shafts 26 and 42, respectively.In order that a feed wheel may be readily disconnected from the shaft 26to permit its replacement the drive shaft 26 may conveniently beslidably journaled in the bearing 28 to permit the shaft to be raisedfrom engagement with the stud shaft 2!.

Rising from the frame [0. is a plurality of spaced brackets 30 providingalined bearings 3! for a pair of spaced alined horizontally disposedgrinding wheel shafts 32, 33 disposed one on each side of the feed wheelshaft 25 and each carrying at its inner end a grinding wheel 34, 35.Shafts 32, 33 are constantly driven from any suitable driving source. Ashere shown, the

' driving connections comprise pulleys 36, 31 on said shafts 32, 33 andbelts 38, 39 trained over said pulleys and over other pulleys 40 and 4|on shaft 42 which shaft thus drives both the feed wheel shaft 26 and thepair of grinding Wheel shafts 32, 33.

In order to insure that the Work pieces Will be tightly held againstmovement in their pockets while the grinding wheels are at work, Iarrange in the cut-outs B and C spring-tensioned pressure shoes 43, 44.The faces of said shoes bear against the band spring l8 at said cutoutsand force it inwardly into tight clamping engagement with the workpieces, the shoe faces being preferably curved to conform to the generalcurvature of said spring and being made long enough to span several ofthe work-holding pockets.

The shoes are spring-tensioned as follows. Each shoe is pivoted at 45,45 on an arm 41, 48, which in turn is pivoted between its ends at 49, tobase II (see Fig. 4). To the free end of each arm 49, 50 is fastened oneend of a coil spring, 5|, 52, the other end of each spring beinganchored to any fixed point as at 53, 54 (see Fig. 2). As a result ofthis construction, the shoes are constantly urged by the springs 5|, 52into pressure engagement with the band spring l8, but may yieldoutwardly to prevent breakage of the parts should such be required.

The finished blanks are discharged one at a time from the feed wheel bymeans of an ejector spring 55 or its equivalent. (see Fig. 2) fixed inthe path of the wheel in the region of the cutout A which acts to rem veeach finished blank from its holding pocket as the wheel rotatestherepast. From the ejector 55 the finished blanks discharge down chute55 into any suitable collection receptacle (not shown) In operation,with the grinding wheels set to make the required grinding cuts, andboth the feed wheel and the grinding wheels revolving, the pockets offeed wheel are loaded with blanks, beginning at approximately the pointI9 in Fig. 3. As said Wheel rotates in the direction of the arrow inthat figure the exposed upper ends of the blanks are successivelycarried beneath and acted upon by the pair of grinding wheels. When thefeed wheel substantially completes its revolution, the finished blanksare ejected one at a time by ejector 55. While the grinding wheels areat work on the blanks, the pressure shoes 43, 44 acting throughretaining spring 18, press them firmly into their pockets.

From the foregoing description it will be evident that the operation iscontinuous and positive. By changing feed wheels, blanks of differentdiameters and lengths may be worked upon.

While I have shown a practical embodiment of my invention whichsatisfactorily fulfills its intended purpose, I recognize that mymachine is susceptible of various changes in design and arrangement. Forexample, it might be equipped with an automatic blank feeding device. Orfor some grading operations, only one grinding Wheel might be required.

These and similar modifications are to be regarded within the scope ofmy invention as defined in the appended claims.

What I therefore claim and desire to secure by Letters Patent is:

1. A grinder, comprising a feed wheel having a peripheral series ofspaced pockets of a shape and depth each to contain a blank endwisetherein with one end of the blank projecting beyond one face of saidfeed wheel, means for rotating said feed wheel in a constant direction,

a grinding wheel positioned to rotate in a path which intersects thatdescribed by the projecting ends of the blanks contained Within thepockets of the feed wheel, means for rotating said grinding wheel, meansfor confining the blanks in said pockets for a portion of the revolutionof said feed wheel, and means for applying additional pressure againstthe blank-confining means at that portion of the arcual travel of theblanks at which they are acted upon by said grinding wheel thereby toseat the blanks tightly in the pockets while they are being acted uponby said wheel, and means for successively ejecting the finished blanksfrom said pockets after they have been acted upon by said grindingwheel. 7

2. A grinder comprising a frame, a base surrounding the frame, a feedwheel rotatable in a horizontal plane over said base and having aperipheral series of spaced vertically disposed pockets of a shape anddepth each to contain a blank endwise therein with one end of the blankprojecting beyond the upper face of the feed wheel, means forcontinuously rotating said feed wheel in the same direction, a pair ofspaced oppositely disposed grinding wheels rotating about spaced alinedaxes over the upper face of the feed wheel in paths which intersect thatdescribed by the projecting ends of the blanks contained in the pocketsof the feed wheel, means for continuously rotating said grinding wheels,means for confining the blanks in said pockets during a substantialportion of the revolution of said feed wheel and while said blanks arebeing successively acted upon by said grinding wheels comprising a bandspring encircling aportion of the periphery of the feed wheel andspring-tensioned pressure shoes for exerting prcssureon said spring atthose portions thereof at which the grinding wheels are acting upon theblanks thereby to seat the blanks tightly. in the pockets oithe feedwheel while they are being acted upon by the grinding wheel, and meansfixed in the path of said feed wheel for successively ejecting thefinished blanks from said pockets after they have been acted upon byboth grinding wheels.

ARDEN B. MACNEILL.

